The present invention generally relates to manufacturing of large structures using composite materials and, more particularly, to a large, mobile robotic arm for manipulation of the mandrels used for laying up composite laminate material for the manufacture of large aircraft fuselage sections.
The structural performance advantages of composites, such as carbon fiber epoxy and graphite bismaleimide (BMI) materials, are widely known in the aerospace industry. Aircraft designers have been attracted to composites, for example, because of their superior stiffness, strength, and lower weight. As more advanced materials and a wider variety of material forms have become available, aerospace usage of composites has increased. Composite materials have been applied using contour tape laminating machines (CTLM) and automated fiber placement machines (AFPM), for example, in the manufacture of parts such as wing panels and empennage. New and innovative composite lamination technologies are envisioned, such as the manufacture of large aircraft fuselage sections that may exceed, for example, 15 to 20 feet in diameter. New super-efficient aircraft—with the majority of the primary structure, including the fuselage and wing, made of composite materials—are contemplated that, in addition to bringing big-jet ranges to mid-size airplanes, will provide airlines with unmatched fuel efficiency, resulting in exceptional environmental performance. It is expected that such aircraft may use 20 percent less fuel for comparable missions than any other current wide-body airplane yet be able to travel at speeds similar to today's fastest wide-bodies, about Mach 0.85, and provide 40 to 60 percent more cargo revenue capacity.
For the manufacturing of comparatively smaller parts, such as wing panels and empennage, the CTLM and AFPM technologies have become highly developed. Since composite materials have material characteristics that differ from traditional aircraft materials, however, it will generally not be possible to use existing facilities and equipment for the construction and assembly of the new, large, composite material aircraft. For example, the large fuselage sections to be made out of a composite material, and which can be described as having a one-piece barrel shape, could be approximately 24 feet long with a diameter of about 20 feet and, therefore, quite large. This large fuselage barrel is a one-piece composite part that could be built by being laid up on a large, multi-piece mandrel whose outer surface is the inner mold line (IML) of the aircraft fuselage. The multi-piece mandrel must be assembled from segments prior to lay-up and disassembled after part cure, i.e., after curing of the composite material, such as a graphite/epoxy, the inner mold line mandrel needs to be removed. A method and equipment will be required for assembling and disassembling the large, heavy mandrel segments.